1. Field of the Invention
The present invention relates to a driving circuit for a light emitting element, an exposure head, and an image forming apparatus.
2. Description of the Related Art
An exposure head that uses light emitting elements such as organic electroluminescence (EL) elements and is mounted to a printer or the like, for example, is constituted by linearly arranging a plurality of pixels having the light emitting elements on a substrate. For that reason, the exposure head has a shape to be elongated in an array direction of the pixels to have a high aspect ratio. At this time, the exposure head preferably has a smaller area as more patterns can be produced at the time of mass production so that costs are reduced. In particular, a variation in the length in a traversal direction significantly affects the area, and this length is preferably set to be shorter as much as possible. At the same time, high speed driving such as an increase in a printing speed is also demanded for the exposure head. To realize these configurations, block driving for collectively writing data to a plurality of pixels by a plurality of data lines is preferably employed.
A plurality of leading lines are connected to a single data line via a contact hole in the block driving. Since a part covering the contact hole by the data lines tends to be wider than the other part, a problem occurs that it is difficult to decrease a distance between the data lines, and it is difficult to reduce the area occupied by the data lines.
Japanese Patent Laid-Open No. 2011-002502 discloses a technology of narrowing line intervals by shifting land parts covering the contact holes in a line lengthwise direction.
However, according to Japanese Patent Laid-Open No. 2011-002502, a first land part is formed so as to protrude from a first line part in only one direction, and a second land part is formed so as to protrude from a second line part in only the same direction as the protrusion of the first land part. For that reason, the interval of the adjacent lines is not sufficiently narrowed. In addition, Japanese Patent Laid-Open No. 2011-002502 does not disclose a manner in which the line interval is narrowed in a case where a plurality of lines each having three or more land parts are arranged.